Underwater divers often need to find their way back to an anchored surface craft, to relocate an earlier-discovered object, to keep track of a companion diver, or to otherwise navigate underwater with respect to a particular reference location. Poor underwater visibility frequently makes visual navigation difficult or impossible, and a diver must rely on dead reckoning or a compass to obtain his bearings. Often, the diver is required to surface to obtain proper bearings. This is an onerous requirement, and may even be dangerous in some instances.
The use of a compass may be difficult and unreliable if multiple turns are executed and turns are spaced apart by great distances. Small errors can result in large deviations from proper locations. Due to the errors inherent in such underwater navigation techniques, many divers constantly check their bearings. This can be wasteful of valuable underwater dive time as well as being inaccurate.
Therefore, the art has included several designs intended to improve a diver's underwater navigation capabilities. However, most of these designs are difficult and cumbersome to use and carry. Still other devices require a diver to orient the device in various directions until a proper bearing is discovered. This requirement may be time consuming and still not be entirely accurate.
Still further, it is often important for a diver to know how far away he is from the reference location. This will give him information regarding how much farther he can move and the like. Many devices presently available in the art do not readily provide such distance from base information.
Therefore, there is a need for an underwater guidance apparatus that is easy to carry and easy to use while still being accurate and while still providing information regarding a diver's distance from a reference location.